Fluoropolymers are generally well known for their chemical and thermal resistance. Partially fluorinated polymers, however, usually have some weakness towards certain types of chemicals, particularly bases. Such polymers often undergo dehydrofluorination or other reactions in the presence of bases, making them unsuitable for use in basic environments. This is particularly true for partially fluorinated polymers which are elastomers, since they are often used as seals for systems which are basic. For this reason, partially fluorinated polymers which are relatively stable to bases have been sought.
U.S. Pat. No. 3,159,609 describes copolymers of tetrafluoroethylene (TFE) and alkyl trifluorovinyl ethers. These polymers are not described as being readily crosslinkable.
U.S. Pat. Nos. 4,158,678, 4,243,770, 4,948,852 and 4,973,633 describe the use of organic iodides as chain transfer agent in fluoromonomer polymerizations. None of these references teach the polymers of this invention.